Scanning laser optical tomography in a neuropathic mouse model : Visualization of structural changes.

BACKGROUND: In the field of hearing research a variety of imaging techniques are available to study molecular and cellular structures of the cochlea. Most of them are based on decalcifying, embedding, and cutting of the cochlea. By means of scanning laser optical tomography (SLOT), the complete cochlea can be visualized without cutting. The Cav1.3-/- mice have already been extensively characterized and show structural changes in the inner ear. Therefore, they were used in this study as a model to investigate whether SLOT can detect structural differences in the murine cochlea. MATERIALS AND METHODS: Whole undissected cochleae from Cav1.3-/- and wild-type mice of various postnatal stages were immunostained and analyzed by SLOT. The results were compared to cochlea preparations that were immunostained and analyzed by fluorescence microscopy. In addition, cochlea preparations were stained with osmium tetraoxide. RESULTS: Visualization by SLOT showed that the staining of nerve fibers at P27 in Cav1.3-/- mice was almost absent compared to wild-type mice and earlier timepoints (P9). The analysis of cochlea preparations confirmed a reduction of the radial nerve fibers. In addition, a significantly reduced number of ribbon synapses per inner hair cell (IHC) at P20 and P27 in the apical part of the cochlea of Cav1.3-/- mice was detected. CONCLUSION: The visualization of whole non-dissected cochleae by SLOT is a suitable tool for the analysis of gross phenotypic changes, as demonstrated by means of the Cav1.3-/- mouse model. For the analysis of finer structures of the cochlea, however, further methods must be used.

[Scanning laser optical tomography in a neuropathic mouse model : Visualization of structural changes. German version]. / Scannende laseroptische Tomographie in einem neuropathischen Mausmodell : Visualisierung von strukturellen Veränderungen.

BACKGROUND: In the field of hearing research a variety of imaging techniques are available to study molecular and cellular structures of the cochlea. Most of them are based on decalcifying, embedding, and cutting of the cochlea. By means of scanning laser optical tomography (SLOT), the complete cochlea can be visualized without cutting. The Cav1.3-/- mice have already been extensively characterized and show structural changes in the inner ear. Therefore, they were used in this study as a model to investigate whether SLOT can detect structural differences in the murine cochlea. MATERIALS AND METHODS: Whole undissected cochleae from Cav1.3-/- and wildtype mice of various postnatal stages were immunostained and analyzed by SLOT. The results were compared to cochlea preparations that were immunostained and analyzed by fluorescence microscopy. In addition, cochlea preparations were stained with osmium tetraoxide. RESULTS: Visualization by SLOT showed that the staining of nerve fibers at P27 in Cav1.3-/- mice was almost absent compared to wildtype mice and earlier timepoints (P9). The analysis of cochlea preparations confirmed a reduction of the radial nerve fibers. In addition, a significantly reduced number of ribbon synapses per inner hair cell (IHC) at P20 and P27 in the apical part of the cochlea of Cav1.3-/- mice was detected. CONCLUSION: The visualization of whole non-dissected cochleae by SLOT is a suitable tool for the analysis of gross phenotypic changes, as demonstrated by means of the Cav1.3-/- mouse model. For the analysis of finer structures of the cochlea, however, further methods must be used.

[Ischemic preconditioning in a rat adipocutaneous flap model]. / Der epigastrisch adipokutane Lappen am Tiermodell zur Evaluierung der ischämischen Präkonditionierung.

INTRODUCTION: Flap necrosis in ear, nose, and throat surgery, especially in high-risk groups, is not rare, but not all of the individual pathophysiological processes are known. The objective of this study was to establish an animal model to determine whether acute ischemic preconditioning, which has been reported to be successful in organ transplantation, will result in enhanced flap survival. METHODS AND MATERIALS: Forty-two Wistar rats were divided into three experimental groups. An epigastric adipocutaneous flap, based on both superficial epigastric arteries and veins, was raised. The flap was either raised (control), clamped for 2 h (ischemic), or subjected to ischemia of 30 min, followed by 30 min of reperfusion and another 2 h of induced ischemia (IP). The mean flap necrosis area was assessed in all groups on the 5th postoperative day. RESULTS: All animals were doing well on the final day. The average necrosis in the ischemic group was significantly greater than in the control group. No significant superiority in the IP group was demonstrated. CONCLUSION: The data show that the experimental animal model is practicable and that additional approaches to ischemic preconditioning should be verified.